202 
The Ohio Naturalist. 
[Vol. XI, No. 1, 
In the deeper water it is a pure Nelumbo lutea family; in the shal- 
lower, the other plants, especially Potamogeton pectinatus and the 
variety are quite abundant. There is some evidence of vertical 
zonation or layering; in the deeper water the Nelumbo leaves float 
on the surface; and in the shallower rise 12 inches above the 
surface. 
Fig. i. View of the vegetation from the S. E. side of the island in 
belt transect a-a r , showing formation I, II and III ; and societies i, 2, 3, 
4, 5, 6 and 7 of map. 
2. Nelumbo-Polygonum society. 
Facies. 
Nelumbo lutea. 
Secondary species. 
Ceratophyllum demersum. 
Spirogyra sp. 
Lemna minor. 
Cladophora sp. 
Spirodela polyrhyza. 
Polygonum emersum. 
Brachythecium rivulare. 
Riccia fluitans. 
Riccia sp. 
Ilysanthes gratioloides. 
Sium cicutaefolium. 
This society forms a dense zone 60 feet broad, and extends 
from water 8 inches deep to a wholly emersed surface. 35 feet 
of the zone covers a mud flat which is submerged at the normal 
water level. The Polygonum has advanced into the Nelumbo, 
